Squid 2.5, when processing the configuration file, parses empty Access Control Lists (ACLs), including proxy_auth ACLs without defined auth schemes, in a way that effectively removes arguments, which could allow remote attackers to bypass intended ACLs if the administrator ignores the parser warnings. (CAN-2005-0194)

Race condition in Squid 2.5.STABLE7 to 2.5.STABLE9, when using the Netscape Set-Cookie recommendations for handling cookies in caches, may cause Set-Cookie headers to be sent to other users, which allows attackers to steal the related cookies. (CAN-2005-0626)

Squid 2.5.STABLE7 and earlier allows remote attackers to cause a denial of service (segmentation fault) by aborting the connection during a (1) PUT or (2) POST request, which causes Squid to access previosuly freed memory. (CAN-2005-0718)

In addition, due to subtle bugs in the previous backported updates of squid (Bugzilla #14209), all the squid-2.5 versions have been updated to squid-2.5.STABLE9 with all the STABLE9 patches from the squid developers.